In discussions of the Bernoulli equation, the distinction between gauge pressure and atmospheric pressure is crucial. When analyzing systems, gauge pressure is considered zero at points where fluid exits to the atmosphere, indicating that the absolute pressure equals atmospheric pressure. Conversely, when calculating pressures within the system, both gauge and atmospheric pressures are relevant. This differentiation is essential for correctly applying Bernoulli's principle in fluid dynamics problems. Understanding these concepts clarifies why one side of an equation may involve gauge pressure while the other does not.
